What is the recommended treatment for scalloping of the fingernail due to a foreign body (FB) granuloma in the cuticle 3 months after a prick from a rose bush?

Treatment of Foreign Body Granuloma in Cuticle with Nail Scalloping

The treatment of choice for a foreign body granuloma in the cuticle causing nail scalloping is intralesional corticosteroid injection (triamcinolone, betamethasone, or prednisolone), repeated in 4-week cycles until resolution, combined with surgical removal of any retained foreign material if present. 1, 2

Initial Diagnostic Imaging

Before initiating treatment, imaging is essential to confirm the presence of retained foreign material:

• Ultrasound is the optimal imaging modality for detecting radiolucent foreign bodies such as wood or plant material from rose thorns, as it allows precise localization and is superior to radiographs for organic material 3
• CT can be used as an alternative if ultrasound is unavailable, though it is better suited for radiodense materials 3
• Radiographs alone are insufficient for rose thorn material, which is typically radiolucent 3

Primary Treatment Algorithm

Step 1: Foreign Body Removal (If Present)

• If imaging confirms retained foreign material, surgical removal must be performed first, as the granuloma will not resolve with retained organic matter 4, 5
• The foreign body triggers ongoing granulomatous inflammation and must be extracted before medical management can succeed 5

Step 2: Intralesional Corticosteroid Therapy

• Inject triamcinolone acetonide, betamethasone, or prednisolone directly into the granuloma tissue 1, 2
• Repeat injections every 4 weeks until the granuloma resolves 1
• This is the most effective treatment for foreign body granulomas and can achieve resolution within weeks if diagnosed and treated early 1

Step 3: Adjunctive Topical Therapy

• Apply mid- to high-potency topical corticosteroid ointment to the nail fold twice daily to reduce inflammation 6, 7
• Perform antiseptic soaks with 2% povidone-iodine or dilute vinegar (1:1 dilution) for 15 minutes twice daily 6, 8
• These measures help control inflammation and prevent secondary infection 6

Management of Complications

If Pyogenic Granuloma Develops

• Apply topical timolol 0.5% gel twice daily under occlusion for 1 month as first-line therapy for periungual pyogenic granuloma 7
• Alternative options include silver nitrate chemical cauterization or scoop shave removal with hyfrecation if timolol fails 7

If Secondary Infection Occurs

• Obtain bacterial cultures before starting antibiotics, as up to 25% of periungual infections have secondary bacterial superinfection 6
• First-line oral antibiotics are cephalexin or amoxicillin-clavulanate (500/125 mg every 12 hours) 6, 9
• If MRSA is suspected or initial therapy fails, use trimethoprim-sulfamethoxazole 6, 9

When to Consider Surgery

Surgical excision should be the last option because foreign body granulomas grow fingerlike into surrounding tissue, making complete excision difficult and likely to leave scars 1, 2

However, surgery is indicated if:

• The granuloma is cystic with little tissue ingrowth 1
• Medical management fails after multiple cycles of intralesional steroids 1
• There is persistent pain or drainage beyond 2-4 weeks despite appropriate treatment 7

Critical Pitfalls to Avoid

• Do not attempt surgical excision as first-line therapy - granulomas have ill-defined borders and surgery tends to be incomplete while leaving deformities 2
• Do not use corticosteroids alone without first removing retained foreign material - the granuloma will persist with ongoing foreign body presence 4, 5
• Monitor for skin atrophy with repeated corticosteroid injections - consider combining with 5-fluorouracil to lower this risk 1
• Do not delay imaging - retained organic material from rose thorns requires ultrasound for detection 3

Follow-Up Protocol

• Reassess after 2 weeks of initial treatment 6
• Continue intralesional steroid injections every 4 weeks until complete resolution 1
• If no improvement after 4-6 weeks of appropriate treatment, refer to dermatology or hand surgery for evaluation 6, 7